1. Technical Field of the Invention
The present invention relates to supplementary services in a cellular telephony network, and more particularly to a barring of outgoing calls in a cellular telephony network.
2. Background of the Invention
Supplementary services in a cellular telephony network are additional features to either teleservices or bearer services. Supplementary services typically provide treatment options for incoming or outgoing calls. With respect to outgoing calls, presently supplementary services in cellular telephony networks only provide three options: barring of all outgoing calls, barring outgoing international calls, and barring all outgoing international calls except those directed to the home PLMN (public land mobile network) country. The first option, barring of all outgoing calls, makes it possible for a mobile subscriber to block all outgoing calls or all calls associated with a basic service. The second option, barring all international calls makes it possible for a mobile subscriber to block international calls outside of the subscriber's home PLMN country. Outgoing calls may only be made to subscribers of the home PLMN and the fixed network of the country where the subscriber is presently located. The present PLMN may be the home PLMN or a visited PLMN. Finally, the third option, barring outgoing international calls except those directed to the home PLMN country, makes it possible for a mobile subscriber to prevent all attempted outgoing international calls except those international calls to the home PLMN country of the mobile subscriber. Outgoing calls are restricted to subscribers of the PLMN and the fixed network of the country where the mobile subscriber is presently located or to mobile subscribers of the home PLMN country of the served mobile subscriber and to subscribers of the fixed network in the home PLMN country. The present PLMN may be the home PLMN or a visited PLMN. This option again may be associated with all services or with a specific basic service.
A mobile subscriber requests the provision of a supplementary service from the service provider of the PLMN. At provision, the mobile subscriber selects the various supplementary services and the manner in which the mobile subscriber may activate the supplementary services. The mobile subscriber may elect two ways to activate the provided supplementary services: by the service provider or by the mobile subscriber with the use of a password. If the mobile subscriber elects for activation by the service provider, the supplementary services can not be activated or changed by the mobile subscriber. Under the second election, the supplementary services may be activated by the mobile subscriber using a password. The service provider must initially register a password for the mobile subscriber which can be changed later by the mobile subscriber. The mobile subscriber may then active the supplementary service by providing the password and information as to whether calls of all services or calls of a specific basic service group should be barred. The mobile subscriber may also change the barring options by issuing commands on a mobile station keyboard and entering the password. Specified command protocols may be used (such as **33* for barring of all outgoing calls) or menu driven applications may be implemented in the mobile station for collection of the barring options from the mobile subscriber. Once activated, the supplementary service is automatically invoked by the cellular telephony network upon a request for an outgoing call not allowed by the active barring option for the corresponding basic service group. If the outgoing call is barred under the active barring option, the network will refuse the outgoing call request and issue a message indicating the rejection to the mobile station. Thus, in a typical cellular telephony network, a mobile subscriber has only three call barring options as part of the supplementary services. A mobile subscriber is unable to elect to bar calls to specific numbers or countries. A need has thus arisen in the industry for more flexible supplementary services for outgoing call barring in a cellular telephony network.